[Carving and ski technique--aspects of biological regulation]

Based on theoretical calculations the effects of skis with great sidecuts on the biological regulation are shown. Of main interest is the overload of the biological system by unexpectedly catching an edge. The calculations show that a great sidecut using the same edge ankle causes a greater lateral deviation compared to a normal ski. The correction of unexpected incidents is done by reflex mechanisms. Remarkable consequences for the reflex time can be calculated for the various sidecuts only. It can be concluded that problems in using carving skis mainly occur in combining high velocities and/or weak movement experiences.

Antitumor activity of oxaliplatin in combination with 5-fluorouracil and the thymidylate synthase inhibitor AG337 in human colon, breast and ovarian cancers

Oxaliplatin, classical [5-fluorouracil (5-FU)] and non-classical (AG337) thymidylate synthase inhibitors have shown promising activity in the treatment of cancer. This study investigates the cytotoxic effects of oxaliplatin in combination with 5-FU and AG337 in cultured human colon (HT29, CaCo2), breast (MCF-7, MDA-MB-231) and ovarian (2008) cancer cell lines, and their derived counterparts selected for their resistance to 5-FU (HT29-5-FU), doxorubicin (MCF-7mdr) or cisplatin (2008C13). Therapeutic experiments were conducted in mice bearing colon-HT29 xenografts and in the GR hormone-independent mammary carcinoma model. In vitro, oxaliplatin shows potent cytotoxic activity in colon (IC50 from 2.1 +/- 1.1 to 5.9 +/- 1.7 microM), ovarian (IC50 = 10 +/- 1.6 microM) and breast cancer cells (IC50 from 7.4 +/- 2.7 to 17.9 +/- 7.1 microM). Oxaliplatin was a potent inhibitor of DNA synthesis and bound to cellular DNA. Surprisingly, the overall amount of oxaliplatin DNA binding was significantly inferior to that induced by isocytotoxic concentrations of cisplatin in HT29 (p=0.026). In vitro, synergistic antiproliferative effects were observed when oxaliplatin was added to 5-FU and AG337. Those synergistic effects of combinations were maintained in colon HT29-5-FU cancer cells. In vivo, 5-FU increased significantly the antitumor activity of oxaliplatin in HT29 xenografts (p=0.0036), and similarly 5-FU and AG337 increased the activity of oxaliplatin in the GR tumor model (p=0.0012). These data may encourage further clinical investigation of oxaliplatin in combination with classical and non-classical thymidylate synthase inhibitors in the treatment of human cancers.

[Implementation and indications for quantitative sialoscintigraphy]

BACKGROUND

Since its introduction in 1965 salivary gland scintigraphy has been an established method to simultaneously investigate excretion function in major salivary glands. In order to elucidate parenchymal function of salivary glands, several authors described various quantitative and semiquantitative methods. However, no standardized protocol for quantitative salivary gland scintigraphy has been established so far.

METHODS

Therefore, in this paper we report on a standardized and validated acquisition protocol for salivary gland scintigraphy using 99mTc-pertechnetate.

RESULTS

A normal data base for both parenchymal and excretion function is given in detail. In addition, the diagnostic value of salivary gland scintigraphy is reviewed in various clinical settings, such as mild parenchymal damage in beginning Sjögren's syndrome, proof of functional obstruction in sialolithiasis with and without parenchymal damage, and parenchymal damage following radioiodine treatment. In a second part, applications of salivary gland scintigraphy in current clinical research are described, and radiation protection of salivary glands in rabbits and patients treated with high doses of I-131 are discussed.

CONCLUSIONS

Salivary gland scintigraphy is a study that is easily performed and well tolerated by the patient. It yields quantitative parameters for parenchymal function and excretion fraction.

Postpartum ultrasonographic diagnosis of inferior vena cava thrombus associated with ovarian vein thrombosis

Postoperative ultrasonographic assessment as a result of unremitting fever after cesarean section depicted a large pedunculated thrombus within the inferior vena cava at the level of the right renal vein. Subsequent imaging studies revealed that this thrombus was the distal extension of right ovarian vein thrombosis into the inferior vena cava.

Effects of olomoucine, a selective inhibitor of cyclin-dependent kinases, on cell cycle progression in human cancer cell lines

We have studied the effects of olomoucine, a selective inhibitor of cdk2, cdc2 and MAP kinase, on the rate of proliferation and the cell cycle progression in human cancer cells in culture. Olomoucine inhibited the growth of the KB 3-1, MDA-MB-231 and Evsa-T cell lines in a concentration-dependent manner, with EC50 values of 45, 75 and 85 microM, respectively. Incubation of exponentially growing KB 3-1 cells in the presence of olomoucine led to an increased proportion of cells in G1 phase after 24 h or more of incubation. Olomoucine failed to rapidly affect the phosphorylation of the Rb tumor-supressor gene product. However, [3H]thymidine incorporation into the cell DNA was rapidly inhibited. We show that this inhibition is due, at least in part, to the diminution of thymidine entry into the cells. Surprisingly, all these cell lines, when synchronized at the G1/S interface and relaxed in the presence of olomoucine, progressed unhindered through the S phase. Under these conditions, the G2 phase transit was markedly retarded but not prevented. Insufficient permeability of the cell membrane to olomoucine may explain the low activity of the drug.

[Peptide-like substances in sheep amniotic fluid which regulate proliferation of BP-A31 cells]

Cell proliferation and differentiation of developing fetus is influenced by hormones as well as insulin-like growth factors and their binding proteins contained in amniotic fluid. Our purpose was to study the actual mitogenic activity of proteins and peptides present in the sheep amniotic fluid. The cell cycle regulatory activity was estimated by using mouse fibroblasts BP-A31 as target cells. The whole amniotic fluid was inactive. However, after removal of small molecules on Sephadex G-10, the fraction eluted in the void volume (M(r) > or = 0.7 kDa) was able to induce the cell division cycle in a significant proportion of quiescent fibroblasts (Fig. 1, fraction A; Fig. 2). By further gel chromatography of this active fraction at acidic condition on Sephadex G-50, two components with mitogenic activity were separated. One component was eluted immediately after the void volume of the column, the other one was coeluted with 125I-IGF-I (Fig. 3). The functional characteristics of mitogenic signal of both components (sensitivity to mitogenic effectors) were similar to those of IGF-I and insulin (Fig. 4). We suppose that a component with higher molecular weight eluted in the vicinity of the void volume of Sephadex G-50 represents probably IGFBPs or other similar proteins.

Direct inhibition of the expression of cyclin D1 gene by sodium butyrate

In the mouse fibroblasts BP-A31 as well as in the human epidermoid carcinoma cells KB-3-1, both cyclin D1 mRNA and protein contents decreased rapidly during incubation with sodium butyrate. The decrease of cyclin D1 mRNA was not prevented by cycloheximide indicating that protein synthesis is not required for the inhibition of the expression of cyclin D1 gene by sodium butyrate. The 973 bp region upstream of the human cyclin D1 gene conferred inhibition of the expression of an indicator gene in transiently transfected cells. An 11 base-pair segment situated within this region, with a strong homology to the butyrate-response consensus element identified in butyrate-inducible promoters, also caused an inhibition of transcription under these conditions, indicating that cyclin D1 expression is inhibited by butyrate at the transcriptional level.

Activation of p21ras is not sufficient to ensure a complete G1 phase of the cell division cycle in mouse fibroblasts

In the mouse BP-A31 fibroblasts, mRNAs coding the three isoforms (Ha, Ki, N) of ras are expressed, and there are no activating mutations in the codons 12, 13 or 61. We have produced a subline (Ras2) expressing an oestrogen-inducible v-Ha-ras gene. The contribution of v-Ha-ras to the overall p21ras-GTP content was evaluated by metabolic labelling with 32P. Surprisingly, p21ras-GTP complexes were predominant in the serum-deprived BP-A31 cells as well as in the Ras2 cells. The excess of p21ras-GTP was not due to the lack of the GTPase activating protein. In transient transfection experiments, the serum response element (SRE)-directed CAT was expressed in serum-deprived BP-A31 cells, and insulin caused a further two- to threefold increase in CAT activity. A dominant negative ras mutant (Ha-Ras Asn-17) cancelled both the basal and insulin-induced CAT expression in the BP-A31 but not in the Ras2 cells. Expression of v-Ha-ras in Ras2 cells did not relax their growth factor-dependence and oestradiol had only a minor mitogenic effect. We conclude that p21ras activation does not ensure a complete cell division cycle in these cells, and does not entirely account for the transduction of the mitogenic signal initiated by insulin.

Synergy between the non-classical thymidylate synthase inhibitor AG337 (Thymitaq) and cisplatin in human colon and ovarian cancer cells

AG337 is the recent non-classical thymidylate synthase inhibitor with promising activity and manageable toxicity in phase I clinical trials. In this study, we investigated the cytotoxic activity of AG337 alone and in combination with cisplatin in cultured human colon (HT29) and ovarian (2008) cancer cell lines and their derived counterparts selected for their resistance to 5-fluorouracil (5-FU) (HT29-5-FU) and cisplatin (2008C13). We observed that AG337 had potent cytotoxic effects in colon (IC50 = 0.17 MicroM) and ovarian cancer cells (IC50 = 0.65 microM). The cytotoxic activity of AG337 was higher than that of 5-FU in the two models. The Activity of AG337 was not significantly affected in 5-FU-resistant HT29-5-FU colon cancer cells characterized by an amplification of the thymidylate synthase gene (IC50 = 0.27 microM, p = 0.15). Combinations of cisplatin and AG337 exert synergistic activity in both ovarian and colon cancer cells. Interestingly, this synergism was maintained in 5-FU- and cisplatin-resistant cells. Therefore, our data encourage further examination of combinations of AG337 with cisplatin in cancer chemotherapy.

Antiproliferative effects of the arotinoid Ro 40-8757 in human gastrointestinal and pancreatic cancer cell lines: combinations with 5-fluorouracil and interferon-alpha

The arotinoid Ro 40-8757 was previously shown to inhibit the growth of a variety of human cancer cell lines derived from breast, lung and uterus. In view of the high incidence of human digestive cancers, and the slow progress in the development of new therapy, we examined in this paper several combinations between the new arotinoid Ro 40-8757, 5-fluorouracil (5FU) and interferon alpha-2a on the growth of nine human cancer cell lines derived from the gastrointestinal and pancreatic system. Half-maximal inhibition of cell proliferation by Ro 40-8757 was observed at concentrations ranging between 0.18 and 0.57 microM, and increased up to 4.7 microM in retinoid-resistant CAPAN 620 pancreatic cells. All-trans-retinoic acid was 70 times less potent. The sensitivity of HT29-5FU-resistant colonic cells was similar to that observed in the parental cells, suggesting an action independent of pyrimidine metabolism. Ro 40-8757 did not induce any differentiation on HT29 cells, as suggested by ultrastructural analysis. The arotinoid did not interact with receptor signal transduction pathways under the control of serum components, such as growth factors as half-maximal inhibiton of growth was similar in HT29-S-B6 cells cultured in the absence or presence of serum. Cell cycle analysis showed that Ro 40-8757 was not acting at a phase-specific transition in HT29 cells and, accordingly, did not induce overexpression of the protein kinase C (PKC)alpha isoform, or conversion of hyperphosphorylated p105 Rb into hypophosphorylated forms. However, the arotinoid induced significant accumulation of the dephosphorylated, active form of the tumour-suppressor protein. Combinations of Ro 40-8757 with 5FU and interferon alpha 2a resulted in an additive but not synergistic antiproliferative action in HT29 cells. Our data support the interest in Ro 40-8757 as a potent anti-cancer drug, especially in combination therapy with 5FU and interferon, in gastrointestinal and pancreatic cancers, where new active therapeutic modalities are urgently needed.

Modulation of [5-125I]iododeoxyuridine incorporation into tumour and normal tissue DNA by methotrexate and thymidylate synthase inhibitors

A potentially useful method for imaging of micrometastases and in situ radiotherapy, would be the incorporation of radioactive labelled iododeoxyuridine (IdU) into tumour DNA. However, there are two main problems: incorporation of the radioactive IdU into normal cells and low incorporation into tumour cells. The aim of this study was to attempt to augment the incorporation of [5-125I]iododeoxyuridine (125IdU) into tumour DNA and to improve the tumour/normal tissue ratio by the use of inhibitors (methotrexate, 5-fluorouracil, AG337, ZD 1694, benzyloxybenzyl uracil) which would prolong the metabolic half-life of the compound. Mammary tumours were induced in GR mice, which were then treated with the inhibitors and the 125IdU. The tumours and representative normal tissue were removed following sacrifice of the animals, and radioactivity within the tissues measured. Pretreatment of mammary carcinoma-bearing GR mice with methotrexate caused approximately a 3-fold increase in the incorporation of 125IdU into tumour DNA, and approximately a > or = 10-fold increase in the tumour/small intestine ratio of incorporated radioactivity. Inhibition of thymidylate synthase, the enzyme involved in IdU dehalogenation, by 5-fluorouracil plus folic acid, or by novel inhibitors AG337 and ZD1694 led to a 3- to 5-fold increase in the 125IdU incorporation. Benzyloxybenzyl uracil, an inhibitor of dihydrouracil dehydrogenase, had little effect. Treatment of tumour-bearing mice with methotrexate plus ZD1694 significantly reduced the rate of tumour growth, but addition of 125IdU (70 microCi/mouse, three daily injections) had no additional antitumour activity. In conclusion, these results do not support the hypothesis that systemic administration of 125IdU can be used for cancer therapy or for imaging purposes unless better methods are found to boost its incorporation into tumour DNA.

Observations on two cases of apparent submandibular gland cysts in HIV positive patients: MR and CT findings

OBJECTIVE

To present two cases of probable lymphoepithelial cysts of the submandibular glands in patients who were human immunodeficiency virus (HIV) positive and who also had lymphoepithelial cysts of the parotid glands.

MATERIALS AND METHODS

Computed tomography and MRI of two HIV positive patients with lymphoepithelial cysts of the parotid glands and cysts in the submandibular glands were correlated with the histories and the possible presence of other known causes of submandibular gland multiple cysts.

RESULTS

Because of the present treatment philosophy regarding HIV positive patients with major salivary gland cysts, surgical resection of these glands was not performed. All other known causes of multiple submandibular gland cysts were excluded by either history or laboratory data.

CONCLUSION

Computed tomography and MRI on two patients with known HIV infection and bilateral parotid lymphoepithelial cysts are presented. Both patients also had bilateral multiple submandibular gland cysts and no evidence of obstructive glandular disease, autoimmune disease, or other organ system cysts. These cases of presumed submandibular gland lymphoepithelial cysts are rare in the literature. They are presented in the hope that other radiologists will be stimulated to document the occurrence of this entity.

Sodium butyrate inhibits the phosphorylation of the retinoblastoma gene product in mouse fibroblasts by a transcription-dependent mechanism

In the chemically transformed mouse fibroblasts BP-A31, the retinoblastoma protein (pRB) is hypophosphorylated at quiescence and becomes hyperphosphorylated after approximately 6 h of serum stimulation. Phosphorylation of pRb was blocked if sodium butyrate was added together with serum or within 3 h afterwards. Actinomycin D added 3 h after serum stimulation did not prevent pRb phosphorylation, but it reversed the inhibitory effect of butyrate. These observations indicate that sodium butyrate acts by turning on the expression of gene(s) coding for proteins which prevent the accumulation of hyperphosphorylated pRb. Such butyrate-induced inhibitor(s) may interfere with the phosphorylation of pRb by cyclin-dependent kinases. Treatment of quiescent BP-A31 cells with serum in the presence of sodium butyrate has led to an increased cell content of the Waf1/CIP1 mRNA (coding for a cyclin-dependent) kinase inhibitory protein) compared with serum alone, suggesting a possible role of p21Waf1/CIP1. In contrast, the mitogen activated protein kinase (enzyme which has been shown to phosphorylate pRb) was constitutively active in BP-A31 cells, and its activity was not significantly affected by a < or = 3h incubation with sodium butyrate.

Left ventricular dysfunction induced by occlusion of coronary arteries in conscious dogs

The aim of the present study was to investigate stable left ventricular dysfunction resulting from severe myocardial ischemia in conscious dogs, in order to evaluate the action of cardiotonic agents under pathological conditions mimicking moderate cardiac failure. Mongrel dogs with a catheter implanted in the left ventricle were trained on a treadmill and subjected to a standardized exercise before and after a Harris-type ligation of the anterior descending branch of the left coronary artery in two stages. Two weeks later the lower third of the left circumflex coronary branch was also occluded, and the exercise test repeated for at least two additional weeks to evaluate the changes in the left ventricular function indicated by left ventricular systolic pressure, end-diastolic pressure, heart rate, positive and negative dP/dtmax and dP/dt/P. Noninvasive radionuclide investigations of the left ventricular function and myocardial perfusion were done before and after the development of cardiac failure. Following occlusion of the anterior descending and circumflex coronary arteries, the baseline end-diastolic pressure increased from 7.6 +/- 2.3 mmHg to 23.3 +/- 3.0 mmHg (p < 0.05) and increased even further during exercise (to 49.2 +/- 3.5 mmHg, p < 0.05). After the development of cardiac failure, no substantial change occurred in the end-diastolic pressure, either during rest or repeated exercise tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of cell cycle progression by sodium butyrate in normal rat kidney fibroblasts is altered by expression of the adenovirus 5 early 1A gene

The effect of sodium butyrate (NaBut) on cell growth was studied in normal rat kidney (NRK) fibroblasts, and in NRK cells stably transfected with either the adenoviral gene E1A (wild-type), or mutated E1A (E1Amut; with a deletion in the CR1 domain), or with the transforming Ha-ras (EJ) gene. The growth of all these cell lines was inhibited by milimolar concentrations of sodium butyrate (NaBut). However, whereas the NRK cells as well as the NRK-E1Amut and NRK-ras cells were arrested in the G1 phase of the cell cycle, the NRK-E1A cells progressively accumulated in the G2 phase, suggesting that the E1A gene expression caused a "leaky" inhibition of G1 phase progression. The expression of late cell cycle-related genes cdc2 and PCNA (proliferating cell nuclear antigen) was not affected by NaBut in the NRK-E1A cells while it was totally suppressed in the other NRK-derived cell lines.

Antiproliferative effects of sodium butyrate in adriamycin-sensitive and -resistant human cancer cell lines

The proliferation of the MCF7 and MCF7-A (adriamycin-resistant) and KB-3-1 and KB-A (adriamycin-resistant) cell lines was arrested by sodium butyrate (NaBut) at 1 mM or higher concentrations. In the MCF7 and MCF7-A cell lines, an accumulation in the G1 phase was observed, whereas the KB-3-1 and KB-A cell lines accumulated in both G1 and G2/M phases. The level of the mRNA coded by the 'early G1' gene c-myc was high in all these cell lines, and was only transiently decreased by NaBut treatment. The 'late' mRNA coding for the proliferating cell nuclear antigen (PCNA) was also strongly expressed in all the cell lines studied; incubation with NaBut caused a decrease of the PCNA mRNA in the MCF7 and MCF7-A cells but not in the KB-3-1 and KB-A cells. The anti-oncoprotein p105RB was undetectable in the MCF7 and MCF7-A cells, while the KB-3-1 as well as KB-A cells contained a high level of this protein. Neither the content nor the apparent state of phosphorylation of the RB protein were affected by incubation (up to 48 h) with NaBut.

The arotinoid Ro 40-8757 has antiproliferative effects in drug-resistant human colon and breast cancer cell lines in vitro

We have examined the antiproliferative effects of the arotinoid Ro 40-8757 in 3 drug-resistant human adenocarcinoma cell lines: the colonic cells HT29-5FU and CaCo2, and the mammary cells MCF-7mdr1. Whereas all-trans retinoic acid had no effect at the concentration of 10(-6) M, Ro 40-8757 was found to exert a high antiproliferative action with similar inhibitory potency (IC50) in drug-resistant and parental cell lines (range, 0.06 x 10(-6) to 0.57 x 10(-6) M). We conclude that: (1) thymidylate synthase is not involved in the mechanism of action of Ro 40-8757; (2) the mdr1 gene product does not recognize this retinoic derivative, and (3) Ro 40-8757, alone or in combinations with other cytotoxic drugs, can be very useful in patients with progressive disease after conventional chemotherapy.

[Value of the ejection fraction in patients with right ventricular necrosis during the rehabilitation period]

The right ventricular ejection fraction was determined in 58 patients with simultaneous right and left ventricular myocardial infarction and in 77 patients with only left ventricular myocardial infarction. The results were analysed in four groups of patients (patients with anterior, anterior and right ventricular, posterior, posterior and right ventricular myocardial infarction). Furthermore, the relation between left and right ventricular ejection fraction, stress capacity and heart volume was investigated. There was no influence of the age and gender of patients on the observed values of right and left ventricular ejection fraction. In younger patients, after myocardial infarction, the heart volume was found to be less and the stress capacity to be higher then in elderly patients. The right ventricular ejection fraction was normal in patients with "poor" left ventricular infarction, and it was decreased in patients with right ventricular myocardial infarction. The right ventricular ejection fraction did not influence the stress capacity and the heart volume of the patients. The left ventricular ejection fraction found to be less in anterior, compared to posterior myocardial infarction. This difference was independent on the presence of right ventricular infarction. The authors consider the decreased right ventricular ejection fraction as a valuable indicator of the abnormal contractility of the right ventricle even at the time of the rehabilitation after myocardial infarction.

Cell cycle dependent regulation of cdc2 mRNA in mouse fibroblasts: requirement of protein synthesis and of continued mitogenic stimulation

In the chemically transformed mouse fibroblasts (BP-A31) placed in a serum-free medium, the cdc2 mRNA content decreases in parallel with the cessation of [3H]thymidine incorporation. Extinction of the cdc2 gene expression is also observed in BP-A31 cells overexpressing the human c-myc oncogene. At quiescence, the cdc2 gene expression can be reinduced with serum or with other mitogens such as insulin or 12-O-tetradecanoyl phorbol 13-acetate (TPA). The kinetics of induction is characterized by a lag period which differs according to the mitogen used and reflects the length of the G1 phase (4-6 h with insulin or serum, 9-12 h with TPA). The cdc2 mRNA accumulation is prevented when protein synthesis is blocked with cycloheximide, also if the drug is added at a time when the synthesis of cdc2 mRNA is already under way. Similarly, removal of the mitogen leads to a cessation of the cdc2 mRNA accumulation. These results suggest that the increased expression of the cdc2 gene is mediated by (a) short-lived, growth factor-regulated protein(s).

Mitogenic signaling by prostaglandins in chemically transformed mouse fibroblasts: comparison with phorbol esters and insulin

In the quiescent mouse BP-A31 fibroblasts, prostaglandin F2 alpha (PGF2 alpha) induces the expression of cell cycle-related genes c-fos, c-jun, and c-myc, and after a delay of approximately 12 h the entry into the phase of DNA replication. A weaker mitogenic effect was produced by certain other PGs (F1 alpha > D2), whereas the effects of PGs E and I were marginal or absent. The mitogenic effects of PGF2 alpha as well as of 12-O-tetradecanoyl phorbol 13-acetate (TPA; activator of protein kinase C) but not those of insulin (acting via the insulin-like growth factor 1 receptor) were abolished by a low concentration (7.5 nM) of staurosporine (inhibitor of protein kinase C). Moreover, long-time (24 h) preincubation with phorbol dibutyrate reduced the mitogenic effects of a subsequent exposure either TPA or PGF2 alpha. These observations favor the involvement of protein kinase C in the PGF2 alpha-dependent intracellular signal transduction. However, simultaneous stimulation of the quiescent cells with saturating concentrations of PGF2 alpha and TPA had a greater mitogenic effect than either drug alone, both in cells with and without down-regulation of protein kinase C, indicating that the protein kinase C-dependent signaling does not entirely account for the mitogenic activity of PGF2 alpha.

Prospective evaluation of thallium-201 reinjection in single-vessel coronary patients undergoing coronary bypass surgery

Twenty-two patients with single-vessel left anterior descending coronary artery disease were investigated by means of dipyridamole stress thallium-201 myocardial perfusion scintigraphy, using single photon emission tomography (SPET), 1 week before and 2-5 weeks after coronary bypass surgery. The dose of dipyridamole was 0.56 mg/kg, and the injected activity of 201Tl was 74 MBq. Before surgery, and after completion of the redistribution study, a further 37 MBq of 201Tl was injected. Ten minutes and 1 h later, repeated SPET imaging were performed. SPET images were evaluated both subjectively and semiquantitatively, using a five-grade segmental defect score system, with higher scores for more severe perfusion defects. Before surgery, the 3-h redistribution images revealed complete or partial persistence of the perfusion defects in all patients. On the images taken 10 min after reinjection, these defects were completely filled in four cases, and partially filled in ten cases. Further positive changes were observed on the 1-h post-reinjection images in four cases. Three of the 1-h post-reinjection images exhibited a paradox redistribution. The stress images after surgery corresponded well to the 201Tl distribution on the preoperative 1-h post-reinjection images in 11 cases. The average of the segmental defect severity scores was 17.0 after stress, 10.1 at rest, 7.1 10 min after reinjection and 6.4 1 h after reinjection. After surgery, the average of both the post-stress and the 3-h redistribution scores was 3.1.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ketoconazole on the proliferation and cell cycle of human cancer cell lines

The growth-inhibitory effects of ketoconazole, an antifungal agent which inhibits arachidonic acid lipoxygenases and cytochrome P-450 enzymes, were tested in human colon and breast cancer cell lines. In the serum independent HT29-S-B6 colon cell clone, ketoconazole reduced cell proliferation and [3H]thymidine incorporation in a dose-dependent fashion, with a 50% inhibitory concentration of approximately 2.5 microM. Flow cytometry showed an accumulation of cells in the G0-G1 phase of the cell cycle and a concomitant decrease of the percentage of cells in S phase. Ketoconazole also inhibited [3H]thymidine incorporation in the hormone-independent breast cancer cells MDA-MB-231 and Evsa-T, with respective 50% inhibitory concentration of approximately 13 and 2 microM. The mechanism of action of ketoconazole is unknown. However, another lipoxygenase inhibitor, BW755C, inhibited only weakly [3H]-thymidine incorporation and accumulated the cells in S and G2. Conversely, clotrimazole and SKF525A, inhibitors of cytochrome P-450 enzymes, had effects similar to those of ketoconazole on HT29-S-B6 cells whereas metronidazole and secnidazole, other azole derivatives which do not inhibit cytochrome P-450 enzymes, had no effect. The results suggest that cytochrome P-450 enzyme(s) activity(ies) could be implicated in the antiproliferative effects of ketoconazole.

[False positive results of exercise tests with thallium myocardial scintigraphy]

The authors have examined supposed causes of positive Th-201 stress scintigraphy. Patients were divided into two groups according to the presence of exercise-induced transitory hypoperfusion or in absence of it. In both groups negative coronarograms were verified. Results of two groups were compared according to parameters of the left ventricle function, pulmonary pressure, to the presence of disorder of system stimulus-conduction (LBBB, RBBB), mitral prolapsus, foramen ovale apertum, anomalous coronary anatomy, level of load during exercise, body weight, heart volume-index. Significant difference was found in disorder of left ventricle motion, ejection fraction and in comprehensive value of left ventricle function (F1).

[Ergometric stress test using Tl-201 myocardial perfusion. Tomographic or planar imaging?]

The clinical performance of the planar vs. tomographic ergometric stress 201-Tl myocard perfusion scintigraphy was compared. The results of the investigations of 80 patients were analysed retrospectively. In 59 patients planar, in 21 tomographic imaging was performed. As a consequence of clinical decision making cardiac catheterization was made in all of the patients, within 3 months after the perfusion scintigraphy. The sensitivity of the planar method was 23/27 (85%), the specificity 18/32 (56%), the accuracy 41/59 (69%). The respective values of the SPECT technique were: Sensitivity: 12/12 (100%), specificity 6/9 (66%), accuracy 18/21 (86%). It is concluded, that in comparison to the planar imaging the SPECT technique is superior in the detection of the perfusion abnormalities of the myocard due to significant coronary narrowings.